Method for manufacturing a crossbeam for a heddle frame of a loom and crossbeam obtained by said method

ABSTRACT

The present invention relates to a method for manufacturing a crossbeam for a heddle frame of a loom allowing to make, at low cost and without waste, a lightweight and very rigid crossbeam, whose heddle-support rod is positioned on the support section in an accurate position that is completely linear, controlled and capable of being reproduced. This manufacturing method is characterized in that one uses a rigid model that has at least one rectilinear groove having a width substantially equal to that of the heddle-support rod; one positions the non-rigid heddle-support rod in the groove to make it rectilinear; one lays a glue line on the junction zone; one positions a rigid support section that is not necessarily rectilinear in a predetermined manner on the model and on the heddle-support rod by flattening the glue line, and one maintains the support section and the heddle-support rod integral with the model, at least while the glue is setting.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority under 35 U.S.C. §119 ofFrench Patent Application No. 02.00961, filed on Jan. 25, 2002, thedisclosure of which is expressly incorporated by reference herein in itsentirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a method for manufacturing acrossbeam or slat for a heddle frame of a loom, as well as a crossbeamobtained by this method, this crossbeam having at least one supportsection and one heddle-support rod or bar affixed to this section alonga junction zone.

[0004] 2. Discussion of Background Information

[0005] Heddle frames are well known in the textile industry and aremainly used in looms. Each heddle frame constitutes a rectangularstructure arranged to hold the loom heddles. To this end, thisrectangular structure conventionally has an upper crossbeam formed of asupport section affixed to an upper heddle-support rod, a lowercrossbeam formed of a support section affixed to a lower heddle-supportrod, and two lateral supports assembled to the ends of the crossbeams toform the frame. The main function of support sections is to bring therigidity that the heddle-support rods do not have, and include, asknown, a cross-section that is larger than that of the heddle-supportrods. Furthermore, in order to guarantee the correct functioning of theloom heddles and their sliding over the entire length of the frame, theheddle-support rods must necessarily be linear and parallel to eachother with an accuracy of approximately + or −0.3 mm. It is noted thateach loom heddle is constituted of a metal blade provided at its endswith a loop so that it can be mounted on the heddle-support rods, withan operational clearance, and with an eyelet in its center to hold andguide a warp thread. Therefore, there are as many loom heddles as thereare warp threads, these loom heddles being distributed, for example,over two heddle frames. On the loom, the heddle frames are put in areciprocal vertical movement by an adapted driving mechanism. Forinstance, for a speed of 1200 strokes per minute, each heddle frame ismoved at a speed of 600 cycles per minute. The constant increase inweaving speeds has brought about new mechanical behaviors and technicaldifficulties for heddle frames as well as for loom heddles.

[0006] Currently, the support sections are essentially made of aluminumalloy, and the heddle-support rods are usually made of stainless steeland attached to the support sections by means of rivets in order toobtain a rigid assembly. The use of support sections made of aluminumalloy by extrusion or spinning is an advantageous solution since itallows making, at reasonable cost, support sections having a reducedweight and a very good straightness. Also, the possible lack ofstraightness can be easily corrected by a mechanical straighteningoperation that is made possible due to the specific mechanicalproperties of the metal alloys. This straightness then allows using thealuminum support section as a reference for attaching the heddle-supportrod thereto with rivets, making it straight. Indeed, this heddle-supportrod is not necessarily itself linear, due to its low rigidity.

[0007] Nevertheless, this type of widely used heddle frame has modestperformances in terms of rigidity, and low resistance to mechanicalfatigue. These drawbacks are amplified with the increase in weavingspeeds. In addition, the assembly of the heddle-support rods on thesupport sections by riveting generates concentrations of harmfiilstresses that can prematurely rupture the heddle frames due tosubstantial alternative dynamic biases.

[0008] An attempt has been made to overcome this drawback byincorporating stiffeners made of carbon fibers in the support sections,and by assembling the heddle-support rod by nesting in a groove providedon each support section, as described in U.S. Pat. No. 4,913,194.However, this type of embodiment is complex and very expensive given thenumber and diversity of the parts to be assembled.

[0009] Another solution is to obtain support sections entirely made ofcomposite materials, for example, by pultrusion of thermoset resinsincorporating carbon fibers or glass fibers, and to attach theheddle-support rods by gluing. The composite materials have numerousadvantages:

[0010] in terms of lightness, they substantially reduce the mass andinertia of the frame, thus improving its dynamic behavior, and

[0011] in terms of rigidity in traction and in compression, theyincrease its resistance to mechanical fatigue well beyond that ofaluminum alloys.

[0012] Nonetheless, the performances in terms of straightness arerelatively poor. For example, the average deflection of this type ofsection is approximately 1 mm per 1 meter of length. Knowing that in thefield of heddle frames, the support sections can measure up to 4.2meters, the possible deflection can reach approximately 4 mm. Inaddition, these composite materials allow no straightening, given thatthe resins are thermoset and therefore very rigid and irreversible.Using this type of support section implies a rigorous selection ofsupport sections having an acceptable straightness in order to make aconsistent heddle-support frame and, consequently, high costs given thesubstantial waste that it causes.

SUMMARY OF THE INVENTION

[0013] Other exemplary embodiments and advantages of the presentinvention may be ascertained by reviewing the present disclosure and theaccompanying drawing.

[0014] The object of the present invention is to overcome thesedrawbacks by proposing a method for manufacturing a crossbeam for aheddle frame for a loom, as well as a crossbeam obtained by this method,allowing to make, at low cost and without waste, a crossbeam combiningproperties of lightness and high rigidity, and whose heddle-support rodis positioned on the support section in an accurate position that iscompletely linear, this position being controlled and capable of beingreproduced.

[0015] To this end, the invention relates to a manufacturing method ofthe type indicated in the preamble, characterized in that one uses arigid model having at least one first straight groove having a widthsubstantially equal to that of the heddle-support rod; theheddle-support rod is positioned in the groove to make it straight, aglue line is laid in the junction zone; the support section ispositioned on the model and on the heddle-support rod in a predeterminedmanner and without stress by flattening the glue line; and the supportsection and heddle-support rod assembly is maintained affixed to themodel at least while the glue is setting.

[0016] In a preferred manner, the model and the support section havecomplementary nesting shapes arranged to position the support sectionaccurately with respect to the heddle-support rod.

[0017] In the case where the support section has a substantiallyrectangular cross-section, the model has a second groove, whose ends atleast are straight and parallel to the first groove, this second groovebeing arranged to receive the substantially rectangular cross-section ofthe support section.

[0018] The support section can be non-straight, and the second groove ofthe model can have a width greater than the total width of therectangular cross-section of the support section. In this case, one canuse positioning members adapted to be mounted at the ends of the supportsection, these positioning members having a width substantially equal tothat of the ends of the second groove.

[0019] In order to manufacture a number n of crossbeams, oneadvantageously uses a number n of models, each model being superimposedon the previous one after the corresponding heddle-support rod, glueline and support section have been positioned, and one maintains theassembly of n support sections/n heddle-support rods affixed to thesuperimposed n models, at least while the glue is setting.

[0020] To this end, the invention also relates to a crossbeam of thetype indicated in the preamble, characterized in that the supportsection is rigid, in that the heddle-support rod is non-rigid, and inthat the heddle-support rod is solidly attached by gluing to the supportsection in a straight position obtained by means of a model arranged tomaintain the heddle-support rod with respect to the support section inthis straight position, at least while the glue is setting.

[0021] The support section can be a non-straight section, made ofcomposite materials and obtained by a method selected from the groupthat includes at least extrusion, pultrusion.

[0022] This support section can have a substantially rectangularcross-section that is extended by a straight section adapted to receivethe heddle-support rod. It can also have a substantially rectangularcross-section in which a longitudinal groove adapted to receive theheddle-support rod is provided. This heddle-support rod can be metallicand can have a cross-section selected from the group that includes atleast a T-shape, a J-shape.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention is further described in the detaileddescription which follows, in reference to the noted plurality ofdrawings by way of non-limiting examples of embodiments of the presentinvention, in which like reference numerals represent similar partsthroughout the several views of the drawings, and wherein:

[0024] The present invention and its advantages will be better apparentfrom the following description of an example of embodiment, withreference to the attached drawings, and in which:

[0025]FIG. 1 is a perspective view of a conventional heddle frame for aloom,

[0026]FIGS. 2A and 2B are side views of a crossbeam according to theinvention, before and after assembly, respectively,

[0027] FIGS. 3A-D are partial perspective views of four steps of themanufacturing method according to the invention to make a crossbeam,

[0028]FIG. 4 is a partial perspective view of a step of themanufacturing method according to the invention to make a number n ofcrossbeams, and

[0029]FIGS. 5A and 5B are side views of an alternative embodiment of acrossbeam according to the invention before and after assembly,respectively.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0030] The particulars shown herein are by way of example and forpurposes of illustrative discussion of the embodiments of the presentinvention only and are presented in the cause of providing what isbelieved to be the most useful and readily understood description of theprinciples and conceptual aspects of the present invention. In thisregard, no attempt is made to show structural details of the presentinvention in more detail than is necessary for the fundamentalunderstanding of the present invention, the description taken with thedrawings making apparent to those skilled in the art how the severalforms of the present invention may be embodied in practice.

[0031] With reference to the Figures, the invention relates to a methodfor manufacturing a crossbeam 2, 2′ for the heddle frame 1 of a loom,and a crossbeam 2, 2′ obtained by this method.

[0032] An example of a conventional heddle frame 1 for a loom is shownin FIG. 1. As known, it has two substantially parallel crossbeams 2 thatare assembled laterally by two posts 2″. Each crossbeam 2 is formed ofone support section 3 and one heddle-support rod 4. The heddle-supportrods 4 have the function of holding and guiding a set of loom heddles 5,only two of which are shown, by their loop-shaped ends 50, while takinginto account an operational clearance J. At the center, each loom heddle5 has an eyelet 51 for the passage of a warp thread 6. These loomheddles 5 are generally made of a hardened metallic material, forexample, stainless steel, in order to resist the mechanical stresses. Inorder to ensure this operational clearance J over the entire length ofthe heddle frame 1, the heddle-support rods 4 must be perfectly linearand parallel to each other by respecting an accuracy of approximately +or −0.3 mm.

[0033] With reference to FIGS. 2A and 2B, the support section 3 has asubstantially rectangular cross-section 30 extended by a straightsection 31 that is capable of receiving the heddle-support rod 4 along ajunction zone 40 formed of a planar surface. This heddle-support rod 4can have a horizontal T-shaped cross-section 4 a or a J-shapedcross-section 4 b, depending on the shape of the loops 50 of the loomheddles 5.

[0034]FIGS. 5A and 5B show an alternative embodiment of a crossbeam 2′,in which the support section 3′ has a substantially rectangularcross-section 30 in which a longitudinal groove 33 is provided that iscapable of receiving the heddle-support rod 4′ along a junction zone 40′formed of at least two planar parallel surfaces. The longitudinal groove33 can be oriented parallel to the plane of the support section 3′,according to the example shown, or perpendicularly according to theshape of the heddle-support rod 4′. This heddle-support rod 4′ can havea cross-section in the shape of a horizontal T that is extended by ajunction tab 4′a, a reverse J 4′b, or of an inverted T 4′c, depending onthe shape of the loops 50 of the loom heddles 5.

[0035] In all of the cases, the substantially rectangular cross-section30 of the support section 3, 3′ has a central recess 32 thatadvantageously reduces its mass and material cost. This support section3, 3′ can have other cross-sections, for example, an I-shape.

[0036] With reference to FIGS. 3A-D, the method for manufacturing acrossbeam 2, 2′ according to the invention includes at least thefollowing steps:

[0037] 1. A rigid model 7 is used having at least one first rectilineargroove 70 with a width substantially equal to that of the heddle-supportrod 4, 4′.

[0038] 2. The heddle-support rod 4, 4′ is positioned in the groove 70(see FIG. 3A).

[0039] 3. A glue line is laid on the junction zone 40, 40′, for example,by means of a nozzle 8 (see FIG. 3B).

[0040] 4. The support section 3, 3′ is positioned in a predeterminedmanner on the model 7 and on the heddle-support rod 4, 4′ by flatteningthe glue line.

[0041] 5. The support section 3, 3′ and heddle-support rod 4, 4′assembly is maintained affixed to the model 7, at least while the glueis setting. This setting time can correspond to the polymerization timeof the glue. Depending on the type of glue, one can lay the gluedirectly on the heddle-support rod 4, 4′, and/or directly on the supportsection 3, 3′.

[0042] The model 7 and the support section 3, 3′ have complementarynesting shapes that allow the accurate positioning of the supportsection 3, 3′ with respect to the heddle-support rod 4, 4′. In theexamples shown, the model 7 has a second groove 71 whose ends at leastare rectilinear and parallel to the first groove 70. This second groove71 has a width greater than the total width of the substantiallyrectangular cross-section 30 of the support section 3, 3′. In thisexample of embodiment, one uses positioning members 9 adapted to bemounted at the ends of the support section 3, 3′, these positioningmembers having a width substantially equal to that of the ends of thesecond groove 71. In this example, the complementary nesting shapes areconstituted of the positioning members 9 and the ends of the secondgroove 71. Naturally, one can provide other equivalent shapes.

[0043] With reference to FIG. 3C, these positioning members 9 areconstituted of a T-shaped plate 90, the stem of the T forming a maleportion capable of being nested in the central recess 32 of the supportsection 3, 3′, and the bar of the T having a width equal to that of theends of the groove 71 of the model 7. The manufacturing method then hasa step in which the positioning members 9 are positioned in the ends ofthe support section 3, 3′ (see FIG. 3C) before the support section 3, 3′is positioned in the model 7.

[0044] Using these positioning members 9, or any other equivalent means,allows ensuring an accurate positioning of the ends of the supportsection 3, 3′ with respect to the heddle-support rod 4, 4′, regardlessof the straightness of the support section 3, 3′. Thus, the interval Ibetween the axis A passing through the center of the central recess 32at the ends of the support section 3, 3′ and the central axis B of theheddle-support rod 4, 4′ (see FIG. 1), is accurate and constant for allof the crossbeams 2, 2′ manufactured according to this method,regardless of the straightness of the support section 3, 3′.

[0045] In order to manufacture a number n of crossbeams 2, 2′, one canuse a number n of identical models 7 that are superimposed as shown inFIG. 4. In this case, the models 7 have a rear portion that is widerthan their front portion, forming a female nesting zone 72 and a malenesting zone 73, respectively. The rear zone has two longitudinal edges74 demarcating the female nesting zone 72, the interval between thesetwo longitudinal edges 74 corresponding to the width of the male nestingzone 73.

[0046] This manufacturing method therefore allows obtaining a crossbeam2, 2′ in which the heddle-support rod 4, 4′ is solidly attached to thesupport section 3, 3′ by gluing, in a rectilinear position obtained bymeans of the model 7 that is arranged to maintain this heddle-supportrod 4, 4′ in this position with respect to the support section 3, 3′, atleast while the glue is setting.

[0047] This manufacturing method is particularly advantageous when oneuses a support section 3, 3′ that is made of a rigid material but thatdoes not necessarily have a rectilinear geometry, as well as aheddle-support rod 4, 4′ that does not necessarily have a rectilineargeometry itself, but that is made of a non-rigid material allowing astraightening. This difference in rigidity is obtained from theselection of materials, but also from the differences in cross-section,the cross-section of the heddle-support rod 4, 4′ being distinctlysmaller than that of the support section 3, 3′. Before assembling thesupport section 3, 3′ affixedly to the heddle-support rod 4, 4′, thisheddle-support rod 4, 4′ that constitutes the functional portion of thecrossbeam 2, 2′ is set in a rectilinear position imparted by the model7. The support section 3, 3′ is then assembled to this heddle-supportrod 4, 4′ without being subject to a substantial deformation in theplane of this section. After assembly, during the removal of thecrossbeam 2, 2′ obtained from the model 7, the heddle-support rod 4, 4′remains in its rectilinear position given the substantial difference inrigidity between the support section 3, 3′ and the heddle-support rod 4,4′. Indeed, if the heddle-support rod 4, 4′ tends to reassume itsoriginal shape, the support section 3, 3′, being much more rigid,resists any deformation and sets the heddle-support rod 4, 4′ in theposition imparted by the model 7.

[0048] This manufacturing method is therefore particularly adapted tothe support sections 3, 3′ made of composite materials and obtainedaccording to a continuous method, such as extrusion or pultrusion. Thesecomposite materials are, for example, thermoset resins based on carbonfibers, glass fibers or other fibers. They have the advantage ofconferring to the support section 3, 3′ a very high rigidity thatincreases its mechanical resistance to fatigue while substantiallyreducing its weight. The lack of straightness related to the use ofthese composite materials is no longer a drawback due to the combinationof the model 7 and the positioning members 9, or any other equivalentmeans. However, this manufacturing method can also be advantageous forsupport sections 3, 3′ made, in a conventional manner, of an aluminumalloy, in order to eliminate the preliminary step of straightening. Inthis case, gluing can be replaced by riveting, or any equivalent means.

[0049] The present invention is not limited to the example of embodimentdescribed, but it extends to any modification and alternative that areobvious to one skilled in the art, while remaining within the scope ofthe protection defined in the attached claims.

[0050] It is noted that the foregoing examples have been provided merelyfor the purpose of explanation and are in no way to be construed aslimiting of the present invention. While the present invention has beendescribed with reference to an exemplary embodiment, it is understoodthat the words which have been used herein are words of description andillustration, rather than words of limitation. Changes may be made,within the purview of the appended claims, as presently stated and asamended, without departing from the scope and spirit of the presentinvention in its aspects. Although the present invention has beendescribed herein with reference to particular means, materials andembodiments, the present invention is not intended to be limited to theparticulars disclosed herein; rather, the present invention extends toall functionally equivalent structures, methods and uses, such as arewithin the scope of the appended claims.

What is claimed:
 1. Method for manufacturing a crossbeam (2, 2′) for aheddle frame (1) of a loom, said crossbeam (2, 2′) comprising at leastone support section (3, 3′) and at least one heddle-support rod (4, 4′)affixed to said support section (3, 3′) along a junction zone (40, 40′),wherein one uses a rigid model (7) comprising at least one firstrectilinear groove (70) having a width substantially equal to that ofthe heddle-support rod (4, 4′); one positions the heddle-support rod (4,4′) in said groove (70) to make it rectilinear; one lays a glue line inthe junction zone (40, 40′); one positions said support section (3, 3′)on said model (7) and on the heddle-support rod (4, 4′) in apredetermined manner and without stress by flattening said glue line;and one maintains the support section (3, 3′) and heddle-support rod (4,4′) assembly affixed to said model (7), at least while said glue issetting.
 2. Method according to claim 1, wherein said model (7) and saidsupport section (3, 3′) comprise complementary nesting shapes arrangedto position the support section (3, 3′) accurately with respect to theheddle-support rod (4, 4′).
 3. Method according to claim 2, wherein thesupport section (3, 3′) has at least a substantially rectangularcross-section (30), and wherein the model (7) comprises a second groove(71) whose ends at least are rectilinear and parallel to the firstgroove (70), this second groove (71) being arranged to receive saidsubstantially rectangular cross-section (30) of the support section (3,3′).
 4. Method according to claim 3, wherein the support section (3, 3′)is non-rectilinear, the second groove (71) of said model (7) having awidth greater than the total width of the substantially rectangularcross-section (30) of said support section (3, 3′), wherein one usespositioning members (9) adapted to be mounted at the ends of saidsupport section (3, 3′), these positioning members (9) having a widthsubstantially equal to that of the ends of said second groove (71). 5.Method according to claim 1, wherein, in order to manufacture a number nof crossbeams (2, 2′), one uses a number n of models (7), each model (7)being superimposed on the previous one after having positioned thecorresponding heddle-support rod (4, 4′), glue line and support section(3, 3′), and wherein one maintains the assembly of n support sections(3, 3′) and of n heddle-support rods (4, 4′) affixed to the superimposedn models (7), at least while said glue is setting.
 6. Crossbeam (2, 2′)for a heddle frame (1) of a loom obtained by the manufacturing methodaccording to claim 1, said crossbeam (2, 2′) comprising at least onesupport section (3, 3′) and at least one heddle-support rod (4, 4′)affixed to said support section (3, 3′) along a junction zone (40, 40′),wherein the support section (3, 3′) is rigid, wherein the heddle-supportrod (4, 4′) is non-rigid, and wherein the heddle-support rod (4, 4′) issolidly affixed to said support section (3, 3′) by gluing in arectilinear position obtained by means of a model (7) arranged tomaintain said heddle-support rod (4, 4′) with respect to said supportsection (3, 3′) in this rectilinear position, at least while said glueis setting.
 7. Crossbeam according to claim 6, wherein the supportsection (3, 3′) is a non-rectilinear section.
 8. Crossbeam according toclaim 7, wherein the support section (3, 3′) is made of compositematerials.
 9. Crossbeam according to claim 8, wherein the supportsection (3, 3′) is obtained by a method selected from the groupincluding at least extrusion, pultrusion.
 10. Crossbeam according toclaim 6, wherein the support section (3) has a substantially rectangularcross-section (30) extend by a substantially straight section (31)adapted to receive said heddle-support rod (4).
 11. Crossbeam accordingto claim 6, wherein the support section (3′) has a substantiallyrectangular cross-section (30) and comprises a longitudinal groove (33)adapted to receive said heddle-support rod (4′).
 12. Crossbeam accordingto claim 6, wherein the heddle-support rod (4, 4′) is metallic. 13.Crossbeam according to claim 6, wherein the heddle-support rod (4, 4′)has a cross-section selected from the group comprising at least aT-shape, a J-shape.